PCB has nothing to do with it. You can put an XM-L2 on any board with a 5050 footprint and dedicated thermal pad. That said I concur with djozz, that looks more like the smaller XP-G2 to me, but its hard to be certain without a close-up detailed photo of the LED so we can see the structure better. Like I said, ignore the board and focus on the emitter.

PCB has nothing to do with it. You can put an XM-L2 on any board with a 5050 footprint and dedicated thermal pad. That said I concur with djozz, that looks more like the smaller XP-G2 to me, but its hard to be certain without a close-up detailed photo of the LED so we can see the structure better. Like I said, ignore the board and focus on the emitter.

Ah right okay will going to take the close up photo. Will update later

PCB has nothing to do with it. You can put an XM-L2 on any board with a 5050 footprint and dedicated thermal pad. That said I concur with djozz, that looks more like the smaller XP-G2 to me, but its hard to be certain without a close-up detailed photo of the LED so we can see the structure better. Like I said, ignore the board and focus on the emitter.

Looks like a real one, with the orange peel surface on the corners.
I can’t see if it has the 3rd bond wire (very thin gold wire) next to the die (the square with the yellow phosphor on top).
If it doesn’t have that, it’s a fake.

How do you test your LED?
I assume you made this thread because somethin isn’t working anymore.
If you have 51V on the LED, I would say that the driver is damaged (the thing inn the green wrapper).

What is this light out of?
it’s pretty dirty and the heatsinking is not really there, so maybe from a lawnmower or a work light?

it’s Bike LED light. It’s pretty dirty because dirts from outside slip inside in small gaps. The product desc said that it’s weatherproof, but still dirt can manage to get in.

It’s not working anymore. The heatsink is not there because i just disassemble it

This is how i test my LED :

turn on, then attach test lead to it’s cable, and the reading will come…The led itself not turn on.
by the way, when i tried smacking the led to table (The led and reflector, not whole component smacked), suddenly it went on. But it doesnt last, only 2 hours and it poof again, and i tried to slap again it wont light up.

Im quite new, and thats all i do for this

The only mystery is, 51V. If its over voltage, why it light up for 2 hours??

Btw, what LED do when you overvoltage it? instant kill or secure shut down?

Haha, that would be interesting to see, him taking a measurement while riding a bike

Flip the bike umop-apisdn so that it’s resting on the seat and handlebars (careful it doesn’t press down on the rear-brake lever). Spin the pedal to make the rear wheel spin.

We used to do that even as kids, “feeding” tree-bark into the spokes and calling it an “ice-cream machine”. (Hey, don’t ask me why…)

But that’s how I tested the generator to see what the voltage was. I was expecting (to feed 6V bulbs) anywhere from 3V at moderate speeds to 5V-6V at full speed (for full brightness). Uh, yeah, if the bulbs were in the circuit!

When my meter pegged (analogue) on the 20V range on my first turn of the pedal, I was shocked (only figuratively, ‘though…).

It was a joke, I have 2 bikes (city bike and mtb) and ride almost every day.
Also, modern bikes mostly have front hub generator (my city bike has this) and this one you have to spin quite fast to get it to 60V, like 40km/h fast…

Of course a LED can run at 51V – with the proper series resistor in between. Since you told us the LED would run after smashing, I suspect the LED isn’t properly connected to the board. With the LED anode or cathode disconnected you’ll measure 51V at the positive pad – when connected, only the LED forward voltage of a few volts.
A reflow might help.

The manufacturer might have chosen the relatively high voltage in order to avoid losses in the long thin wires.

Edit:
sorry for double post, just have seen that Lexel had the same idea earlier.

Of course a LED can run at 51V – with the proper series resistor in between. Since you told us the LED would run after smashing, I suspect the LED isn’t properly connected to the board. With the LED anode or cathode disconnected you’ll measure 51V at the positive pad – when connected, only the LED forward voltage of a few volts.
A reflow might help.

The manufacturer might have chosen the relatively high voltage in order to avoid losses in the long thin wires.

Edit:
sorry for double post, just have seen that Lexel had the same idea earlier.

So led with 51V will not kill that led?

Its from driver to led chip directly 51V..do the led chip have integrated resistors or something?

O, it’s a E-Bike, with chunky battery pack, <- Important piece of information.
Have you checked if the coil is connected properly?

How to check it? I dont know which coil… You mean positive and negative solder?

Well, it the voltmeter on your handlebar shows your battery voltage =52V and you are measuring 52V at the led that can only mean that DCDC step down converter is one sick puppy because XML2 led (or any other here common led) can not handel 51V, not even close to that.
If red blinking lights are also connected to the same step down converter that XML2 is connected to, and they still work properly it can only mean that part tha provides power for XML2 led is to blame for this mess.
Red LEDs are usually 3W so electronic that provides power for them is probably not the same as electronic that provides white 10W XML2 LED with power althou they can be on the same PDB.

Check if both wires from coil are still soldered to PCB, sometimes they can break off due to vibrations but when that happens in flashlight it usually loses power.

nvzn wrote:

Its from driver to led chip directly 51V..do the led chip have integrated resistors or something?